The present invention relates to a multitube reactor for carrying out a process for catalytic conversion. Examples of such a conversion are the catalytic conversion of synthesis gas, comprised of carbon monoxide and hydrogen, into middle distillates and the reaction between hydrogenated acetone to form methyl isobutane and water.
Such a multitube reactor comprises a normally substantially vertically extending vessel, a plurality of open-ended reactor tubes arranged in the vessel parallel to its central longitudinal axis of which the upper ends are fixed to an upper tube plate and in fluid communication with a fluid inlet chamber above the upper tube plate and of which the lower ends are fixed to a lower tube plate and in fluid communication with an effluent collecting chamber below the lower tube plate, liquid supply means for supplying liquid to the fluid inlet chamber, gas supply means for supplying gas to the fluid inlet chamber, and an effluent outlet arranged in the effluent collecting chamber.
The upper ends of the reactor tubes are provided with tubes extending through the bottom of a horizontal tray arranged above the upper tube plate.
During normal operation the reactor tubes are filled with catalyst particles. To convert synthesis gas into middle distillates, synthesis gas s supplied through the fluid inlet chamber into the upper ends of the reactor tubes and passed through the reactor tubes. Effluents leaving the lower ends of the reactor tubes are collected in the effluent collecting chamber and removed from the effluent collecting chamber through the effluent outlet.
To distribute the heat of reaction generated during the conversion uniformly over the reactor tubes, and to improve heat transfer from the interiors of said tubes to the inner walls of the reactor tubes, liquid is introduced into the fluid collecting chamber. The liquid which is collected on the bottom of the horizontal tray flows into the upper ends of the reactor tubes. Liquid leaving the lower ends of the reactor tubes is collected in the effluent collecting chamber and removed from the effluent collecting chamber through the effluent outlet.
The heat of reaction is removed by a heat transfer fluid which is passed along the outer surfaces of the reactor tubes.
Such a multitube reactor can also be used for the catalytic conversion of a liquid in the presence of a gas.
A multitube reactor for such processes will have a diameter of about 5 m and between about 5,000 reactor tubes with a diameter of about 45 mm to 15,000 reactor tubes with a diameter of about 25 mm. The length of a reactor tube will be about 10 to 15 m.
Such a reactor will never be exactly vertical, nor will the upper tube plate be exactly flat. Consequently the distances between a horizontal plane and the upper ends of the reactor tubes will vary. As a result there are reactor tubes which during normal operation do not receive liquid. The reactions in these reactor tubes will not be adequately cooled and this will cause overheating of the reactor tubes.
It is an object of the present invention to provide a multitube reactor wherein during normal operation liquid can be substantially uniformly distributed to all reactor tubes when the reactor is slightly tilted or the upper tube plate is slightly sagged, and wherein the gas velocities in the reactor tubes are substantially insensitive to the void fractions in the reactor tubes.